LYME DISEASE RISK ASSESSMENT, FORT MONMOUTH, EATONTOWN, NEW JERSEY, 1-4 JUNE 1992 DEPARTMENT OF THE ARMY U.S. Army Environmental Hygiene Activity - North Fort George G. Meade, Maryland 20755-5225 [Seal of Department of Defense, United States of America] REPLY TO ATTENTION OF: HSHB-AN-P (40-f) 30 SEP 1992 LYME DISEASE RISK ASSESSMENT NO. 16-61-A850-92 FORT MONMOUTH, EATONTOWN, NEW JERSEY 1-4 JUNE 1992 1. REFERENCES. a. Lyme Disease Surveillance Summary, Volume 3, No. 1, March 1992, Centers for Disease Control. b. Burt, W. H. and R. P. Grossenheider, A Field Guide to the Mammals North America north of Mexico, Third Edition, 1976, Houghton Mifflin Company, Boston, 289pp. C. AFPMB Technical Information Memorandum No. 26, Lyme Disease Vector Surveillance Control, March 1990. 2. AUTHORITY. a. Conference Report on the National Defense Authorization Act for Fiscal Years 92 and 93, House Report 102-311, 102nd Congress, 1st Session, 13 November 1991, p.422. b. USAEHA Form 250-R, HSC, 7 August 1991. 3. PURPOSE. To assess the risk of Lyme disease to Fort Monmouth personnel by examining rodents for the tick vector, Ixodes dammini and to assay collected ticks for the Lyme disease causative agent, Borrelia burgdorferi. 4. GENERAL. a. Risk definition. The term "risk", as used in this report, is a non-statistical evaluation of qualitative and quantitative information available to determine the potential to acquire Lyme disease. To the extent available, information evaluated includes the following elements: (1) History of Lyme disease in the area. (2) The presence or absence of the tick vector (I. dammini) and the mammalian host population needed to sustain a viable population of the vector. (3) The presence of the Lyme disease-causing spirochete (B. burgdorferi) in the tick population. Risk categorization criteria are: Low risk - Risk elements identified in nearby areas but minimal involvement on the installation. Moderate risk - Some risk elements identified from the installation or human cases of Lyme disease reported from the local area. High risk - All risk elements present on the installation. b. Personnel Contacted. (1) The purpose and methodology of this assessment were discussed with CPT George Taylor, Environmental Science Officer, Preventive Medicine Service, USA MEDDAC, Fort Monmouth, NJ. (2) Ms. Bonnie Shore, Department of Health Services, State of New Jersey, was contacted for local Lyme disease statistics. c. Survey Conduct. CPT Thomas M. Burroughs, Entomologist, this Activity, conducted this assessment. Ticks were identified and assayed via Direct Fluorescent Antibody (DFA) tests by personnel of this Activity, for the presence of B. burgdorferi. d. Technical Assistance. Technical assistance or further informal advice may be obtained by contacting Chief, Entomological Sciences Division (ESD), this Activity, Commercial Phone (410)-677-5281/6502 or DSN 923-5281/6502. 5. BACKGROUND. a. Lyme disease is a multi-systemic infectious disease caused by the spirochete, B. burgdorferi, which is transmitted to humans by the bite of an infected tick. The disease is most often referred to as Lyme disease or Lyme arthritis in the United States. Lyme disease has become the most prevalent arthropod-borne illness in North America. Its geographic range is expanding and the number of reported cases continues to rise each year. The Office of the Surgeon General reported 379 cases of Lyme disease contracted on Department of Defense (DOD) installations from 1987 through 1991. During 1990, there were 78 cases of Lyme disease treated in military hospitals from all the Armed Services of which 26 of the cases were either dependents or retired members. During 1991, there were 81 cases of Lyme disease treated in miltary hospitals of which 31 of the cases were either dependents or retired members. Three soldiers were reported to have permanent disabilities caused by Lyme disease during 1991. The need to protect soldiers and other personnel working on DOD installations has increased with the spread of Lyme disease. b. In 1991, the state of New Jersey Department of Health Services reported 852 cases of Lyme disease statewide that meet the Centers for Disease Control (CDC) guidelines. There were 133 reported cases meeting CDC guidelines in 1991 in Monmouth County where Fort Monmouth is located. c. Fort Monmouth is located in Monmouth County, Eatontowm, New Jersey. Fort Monmouth consists of the Main Post area, and two sub-posts; the Charles Wood area and the Evans area. Both sub-posts are located within a twelve-mile radius of the Main Post. The total combined area is approximately 1,350 acres. 6. METHODS. a. Field Survey Procedures. Tick Surveys. Ticks were collected using tick drags and from the ears of trapped rodents. (1) Tick Drag Technique. Two narrow boards (1X2X36-inch) were attached on opposite ends of a 3X3-foot white flannel cloth. A cord was fastened to the ends of one board. The cloth was then pulled slowly over vegetation for approximately 10 meters before examination of the cloth for attached ticks. Ticks were then removed from the cloth and placed in a marked vial for that particular dragging operation. Collected ticks were placed in labeled, 20 ml humidified vials and kept cool. Several potential tick habitats were examined using this technique, to include all rodent trap locations. (2) Rodent Surveys. Small mammals were captured in live traps. Five trapping locations were selected at Fort Monmouth and a trap line was set at each location; a total of 75-80 traps were set each evening. Traps were located near brush and debris piles, fence lines, rock piles, and anywhere else offering harborage for rodents. Rodents trapped were identified using "A Field Guide to the of Mammals North America, North of Mexico" (Reference b). All animals were anesthetized with ketamine before removing ticks. All animals were examined under a dissecting microscope for ticks. Ticks found on animals were removed, using fine-point (No. 5) jeweler's forceps, and were retained for bioassay. Collected ticks were placed in labeled, 20 ml humidified vials and kept cool. All anesthetized animals were returned to their trap location and released upon recovery. b. Laboratory Assay Procedures. Ticks were assayed via Direct Fluorescent Antibody (DFA) testing using antibody conjugate from Kirkegaard and Perry Laboratories, Inc. to determine presence of the Lyme disease spirochete, B. burgdorferi. This conjugate is affinity absorbed to minimize cross reactivity with other spirochetes. 7. RESULTS. (See also Appendix A). a. Trapping success was poor with seven White-footed Mice (Peromyscus leucopus) and one Meadow Vole (Microtus pennsylvanicus) being captured. Poor trapping success was attributed to heavy rains occurring on two of the four trap nights, and raccoons stealing the bait from a great many traps in the Charles Wood area. A total of four ticks (Dermacentor variabilis) were collected from two of the eight (25%) rodents. One I. dammini was collected on an area drag of the Charles Wood area. Six D. variabilis were collected from various area drags. b. Lyme disease spirochetes were not observed by DFA staining in either species tested. c. Areas trapped included: the wooded area across from the Charles Wood Shoppette, the golf course, the field behind the TISA building, and the ACOE picnic area. 8. CONCLUSIONS. The Lyme disease vector, Ixodes dammini, was collected at Fort Monmouth. Borrelia burgdorferi, the causative agent for Lyme disease, was not found at Fort Monmouth. Monmouth County, where Fort Monmouth is located, reported 133 confirmed Lyme disease cases in 1991. This information indicates that the risk of acquiring Lyme disease at Fort Monmouth is moderate. However, no human cases have been documented as originating on the installation and the tick vector appears to be scarce. Even though the criteria suggest a moderate risk, the actual risk to troops and dependents on the installation is LOW based upon the relative low population density of I. dammini encountered during this assessment. Implementation of personal protective measures for all military and civilians using Fort Monmouth for outdoor training or recreation is warranted. 9. RECOMMENDATIONS. The low risk category and conditions at Fort Monmouth suggest the need for continued prevention programs and increased surveillance. a. Implement guidelines in Appendix B. The risk of contracting Lyme disease can be minimized by the proper wearing of clothing, by avoiding areas known to harbor high tick populations, and by the proper use of repellents. (See Appendix C for repellent products available in the Defense General Supply Center or Self Service System). b. Conduct annual follow-up surveillance using the methods described in reference c (TIM 26) and paragraph 6 this report. [signature] THOMAS M. BURROUGHS CPT, MS Entomologist APPROVED BY: [signature] GEORGE J. MAGNON CPT, MS Chief, Entomological Sciences Division APPENDIX A DOD LYME DISEASE SURVEY U.S. ARMY ENVIRONMENTAL HYGIENE ACTIVITY-NORTH DATA SUMMARY Table 1. Ticks collected from animal hosts, Fort Monmouth, NJ, 1-4 June 1992. =========================================================================== Host #Hosts Ticks ---------------------------------------------------- I. dammini D. variabilis Total Stage C / T / P / %(1)C / T / P / % C / T / P / % --------------------------------------------------------------------------- larva none 3 / 3 / 0 / 0 3 / 3 / 0 / 0 White-footed Mouse ---------------------------------------------------- P. leucopus 7 nymph none none none ---------------------------------------------------- adult none none none --------------------------------------------------------------------------- larva none none none Meadow Vole ---------------------------------------------------- M. pennsylvanicus 1 nymph none 1 / 1 / 0 / 0 1 / 1 / 0 / 0 ---------------------------------------------------- adult none none none --------------------------------------------------------------------------- Total 8 all none 4 / 4 / 0 / 0 4 / 4 / 0 / 0 --------------------------------------------------------------------------- Table 2. Ticks collected from habitat surveys, Fort Monmouth, NJ, 1-4 June 1992. =========================================================================== Survey Type #Surveys Ticks ---------------------------------------------------- I. dammini D. variabilis Total Stage C / T / P / %(1)C / T / P / % C / T / P / % --------------------------------------------------------------------------- larva none none none ---------------------------------------------------- Drag 9 nymph 1 / 1 / 0 / 0 none 1 / 1 / 0 / 0 ---------------------------------------------------- adult none 6 / 6 / 0 / 0 6 / 6 / 0 / 0 --------------------------------------------------------------------------- Total 9 all 1 / 1 / 0 / 0 6 / 6 / 0 / 0 7 / 7 / 0 / 0 --------------------------------------------------------------------------- (1) C / T / P / % = # Collected / # Tested / # Positive / % Positive for spirochetes. APPENDIX B Lyme Disease Risk Reduction Measures 1. Emphasize public awareness programs to educate troops, dependents, civilian employees and visitors on personal protective measures and Lyme disease. Methods should include, but are not limited to: a. Distribution of printed Lyme disease handouts such as tick identification cards (USAMD-7/89), pamphlets, and fact sheets. b. Notifications in the installation's newsletter and post electronic media (e.g., closed-circuit TV), especially prior to the high-risk months (May-November). c. Making available, for viewing, the video LYME DISEASE: A growing threat (FAUPIN No. 504494DA). A 35 mm slide format presentation on Lyme disease is also available from this Activity. 2. Submit any collected tick specimens (both field-collected or ticks that have been removed from individuals) alive for identification and DFA testing to the Entomological Sciences Division (ESD), U.S. Army Environmental Hygiene Activity-North (USAEHA-North), Building 4411, Fort George G. Meade, MD 20755-5225. 3. Stock Permethrin Arthropod Repellent (NSN 6940-01-278-1336, box of 12 cans for $36.99), and 3M [Trademark] Insect Repellent (NSN 6840-01-284- 3982, box of 12 tubes, $29.30) for distribution. Emphasize tick habitat avoidance and proper wearing of clothing and use of repellents. 4. Report all confirmed and suspected cases of Lyme disease [e.g., suspicious febrile illnesses, arthralgias, rashes, (Erythema Migrans)] by message using the Disease Alert Report Format for all soldiers and civilian beneficiaries. 5. Identify high risk foci in cantonment areas via tick dragging/flagging, small mammal trapping, deer checks and the assaying of collected ticks for Borrelia burgdorferi. Sampling should be performed in early summer when Ixodes dammini nymphs (the life stage responsible for most human Lyme disease infections) are active. Post DA Poster 40-5, and thereby identify high risk areas. DA Poster 40-5 can be obtained by writing to the Commander, U.S. Environmental Hygiene Agency, ATTN: HSHB-MR-E, Aberdeen Proving Ground, MD 21010-5422 or by telephone: DSN 584-3613 or Commercial (410) 671-3613. 6. Avoid high tick population areas for troop training or recreation. Such areas can be identified by dragging or flagging for ticks prior to use. Case by case surveillance is necessary due to the patchy distribution of I. dammini. 7. Eliminate tick habitat in heavily used, infested areas (e.g., wooded recreation areas) by removing low brush and leaf litter. Tick infestations should be verified via tick flagging or dragging prior to habitat modification. Clearing should be done in low risk months. 8. Prepare, as a contingency, to treat high-use areas with pesticides if surveillance reveals high tick numbers and if nonchemical control techniques (e.g., brush removal, mowing, raking) do not provide adequate control. --- [Trademark] 3M is a registered trademark of Minnesota Mining and Manufacturing Co., St. Paul, MN 55133-3053 APPENDIX C REPELLENTS 1. Several repellent products are available through the Defense General Supply Center (DGSC) or Self Service Supply System. When used in accordance with label directions and in conjunction with the proper wearing of the uniform, they provide personal protection against a wide variety of medically important insect/arthropod pests. Availability and current pricing can be obtained by calling the DGSC at DSN 695-4865: a. Insect/Arthropod Repellent Lotion (cream, 2 fluid ounces). The lotion, NSN 6840-01-284-3982, is not labeled for ticks, but will repel chigger mites and many biting flies. b. Permethrin Arthropod Repellent, Insect Repellent, Clothing Application (aerosol, 6 ounces) NSN 6840-01-278-1336. Seventy-five percent of the can is used to apply to the field uniform and the remainder is used to treat mosquito netting. The product provides protection from ticks and mosquitoes for a maximum of five weeks or five launderings. Use more repellent frequently if "buddy checks" reveal attached ticks. c. Insect Repellent Fabric Treatment (liquid, 5.1 fluid ounces) NSN 6840-01-334-2666. The contents are added to 2 gallons of water and applied with the 2-gallon sprayer from a field sanitation kit at a pressure of 50 pounds per square inch to field uniforms, mosquito netting, and tent fabric to provide protection from ticks, biting flies, and other insects. Since most sprayers are not equipped with the required pressure gauge (NSN 3740- 01-332-8746), it will be necessary to obtain a pressure gauge and filter (NSN 4330-01-332-1639), in order to complete the retrofitting. Proper application can provide protection for the normal life of the uniform, six launderings of mosquito netting, and 6-9 months of treatment for tent fabric, depending on the climate. 2. Detailed directions for the use of these and other repellents can be found in the U.S. Army Environmental Hygiene Agency Technical Guide (TG) 174, Personal Protective Techniques Against Insects and Other Arthropods of Military Significance. 3. The U.S. Army Medical Department Tick-Borne Disease Card (7189) is available from U.S. Army Environmental Hygiene Activity-North, ESD.